1. Field of the Invention
The invention relates to a method for the production of a tube made of a pipe element having at least one plastic layer and a multi-layer tube head molded by pressing of heated plastic blanks, with a tube neck opening out centrally in a dispensing opening, and with an outside thread to screw on a closure cap.
2. The Prior Art
Such a method and such a tube are known from EP-A-59281. The tube is produced in that two plastic blanks are issued above one another from two nozzle openings arranged above one another, and jointly brought to a press mold. The press mold consists of a mandrel, the free end of which reproduces the inside shape of the tube head, onto which a pre-finished pipe element is placed, and a die which reproduces the outside shape of the tube head. By applying pressure, the blanks are pressed to produce a layered tube head, which is simultaneously bonded to the pipe element. It is true that two layers can be obtained in this way, but they do not have a uniform arrangement, since even with slight variations in the viscosity or the temperature of the blanks, different flow velocities occur, which result in different distribution of the two blanks in the press mold. Therefore only tubes with two layers in the tube head can be produced. However, there is also a need to produce a tube with three layers, for example, one of which is supposed to be a barrier layer. Plastics with a barrier effect are usually difficult to combine with other plastics, and/or are not allowed to come into contact with the contents of the tube, so that additional covering layers are required as covering and/or insulating layers.